1. Field of the Invention
This invention relates generally to generally to wireless telephony and in particular to multimodal wireless communication devices that support communications between the wireless device and called parties using more than one type or kind of wireless communications technique, e.g., CDMA (or GSM) and Bluetooth. More particularly, the invention relates to a method by selection of a particular communication mode for a call is made via a dialing string input into the device by the user.
2. Description of Related Art
The ubiquitous cellular telephone, and the cellular telephone service provider infrastructure, provides a means by which users can place and receive telephone calls over a widespread geographic region. Cellular telephone services include calling plans by which a user of cellular telephone service are charged for use of “air time,” that is, actual minutes of use of the cellular telephone infrastructure. When the person is “roaming,” i.e., away from their normal calling region, these charges for service can become costly, depending on the plan the user has with their service provider.
There have been several attempts in the art to help reduce the cost of cellular telephone use. These attempts have taken advantage of the observation that a wireless device like a cellular telephone may by built such that it supports wireless communication in two different modes: (1) a conventional cellular telephony mode, in which the phone communicates with an antenna and base station of cellular telephony network, and (2) a “free”, short range radio frequency communication mode that is independent of the cellular telephony infrastructure. An example of mode (2) is radio frequency communication with a cordless telephone base station. When the phone is in mode (2), the calls can be placed and received via land line plain old telephone circuits connected to the cordless telephone base station, thereby avoiding the user of cellular telephony infrastructure and avoiding “air time” and the associated costs.
For example, U.S. Pat. No. 6,141,560 discloses a cellular telephone that has a dual mode of operation. The phone includes a conventional cellular transceiver for making and receiving standard cell phone calls through the cellular infrastructure, and a cordless telephone transceiver for placing calls through the conventional telephone central office and landlines via a cordless telephone base station. Typically, the cordless telephone base station would remain in the home or office, and while the phone is within range of the cordless telephone base station, the unit would place calls via the cordless telephone base station and land line, thereby avoiding air time and the use of the cellular telephone infrastructure. The '560 patent further discloses that the user may provide a preference for initiating a call as either cordless or cellular, but does not specifically teach how such preferences should be indicated. The usefulness of the '560 patent as a dual mode phone is somewhat limited, in that the cordless telephone mode is only available when the phone is within range of the cordless base station, e.g., within 50 or 100 feet or so. It would not offer any dual mode operation when the mobile phone is roaming, for example while the person is in their car or waiting to catch a flight at the airport. In these situations, the phone would only offer convention cellular telephone service.
U.S. Patent application publication no. 2002/0102974 teaches a similar arrangement for a cellular telephone. The phone has an associated cordless telephone base unit, and its usage in a cordless mode is limited to those instances in which the phone is physically proximate to the base unit. The '974 patent teaches that the mobile terminal may include a short-range radio interface, such as Bluetooth, to communicate with the base unit of a cordless telephone system.
U.S. Pat. No. 6,484,027 discloses a wireless handset that is capable of operating within a wireless network (such as a cellular or PCS network), or in direct handset-to-handset radio frequency communication that is independent of the wireless network, i.e., a “free” call. When the user wishes to call a user using the direct handset to handset communication, the user presses a “FREE” button on the handset, the transmitter/receiver or tuner tunes to the registry channel for the other handset and waits for a response indicating that the other handset is within range. If it is within range, a call request is transmitted and a channel is negotiated so that the two handsets can communicate with each other. If the other unit is out of range, the user is prompted to indicate whether the call should continue via the cellular telephone network.
Other references of interest include US patent application publication 2003/0236091; U.S. Pat. No. 6,011,978; European patent application EP 1 289 235 A2; and U.S. Patent application publication 2002/0086636. The entire contents of all of the references cited in this document are incorporated by reference herein.